Low-temperature anomalies in elastic properties of single-crystal (SrAl0.5Ta0.5O3) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si60.svg" display="inline" id="d1e1496"> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>

Two Czochralski grown crystals of the solid solution series (SrAl 0.5 Ta 0.5 O 3 ) 1 − x (LaAlO 3 ) x with slightly different compositional parameter x were investigated for thermoelastic properties and thermal expansion in the temperature range between 103 K and 1673 K. The coefficients of thermal expansion were obtained by high-resolution dilatometry and elastic stiffnesses by resonant ultrasound spectroscopy. The samples show an elastic softening below ambient temperatures indicating precursor effects of a phase transition that likely occurs below 100 K. The onset temperature of these effects depend on the parameter x in the solid solution series. • Detection of precursor effects of a low-temperature phase transition in the perovskite mixed solid solution series (SrAl 0.5 Ta 0.5 O 3 ) 1 − x (LaAlO 3 ) x (LSAT). • Determination of thermoelastic properties of LSAT in the broad temperature range between 100 K and 1673 K, which are crucial for the application as substrate material. • Correlations between variations in stoichiometry and transition temperature by including literature data of the endmember LaAlO 3 could be obtained.